Delivery System for Over the Wire Implantation of a Medical Device

This application claims the benefit of U.S. Provisional Application Ser. No. 63/365,671, filed Jun. 1, 2022, the entire content of which is incorporated herein by reference.

The leadless pacemaker, which is significantly smaller than a conventional pacemaker coupled to one or more transvenous leads, is a self-contained generator and electrode system configured to be implanted directly into the heart. The leadless pacemaker, which does not utilize leads extending from out of the heart of a patient, eliminates several complications associated with transvenous pacemakers and leads such as, for example, pocket infections, hematoma, lead dislodgment, and lead fracture. The leadless pacemaker also has cosmetic appeal because there is no chest incision or visible pacemaker pocket.

The leadless pacemaker includes one or more electrodes on its outer housing to deliver therapeutic electrical signals and/or sense intrinsic depolarizations of the heart. Intracardiac medical devices may provide cardiac therapy functionality, such as sensing and pacing, and may also be used to treat either atrial or ventricular arrhythmias or fibrillation.

The leadless pacemaker device may be implanted via a femoral vein (or jugular vein) transcatheter approach, and requires no chest incision or subcutaneous generator pocket. The system utilized to deploy the leadless pacemaker includes a catheter having a distal end with a delivery cup housing the self-contained generator and electrode system. The delivery cup is maneuvered into the proper position, e.g., in the right atrium at or near the triangle of Koch (TOK) or the right ventricle, under fluoroscopic visualization or using a sonogram produced by an ultrasound imaging system.

Interventional guidewires, known to those skilled in the art of minimally invasive medical procedures, are useful for providing access to remote sites within a patient's body, for example, to deliver diagnostic and/or therapy devices to the sites. In many instances, a guidewire is inserted into the body and steered into position at a target site so that a catheter can be guided to the site over the guidewire. The catheter, as part of an interventional medical system, may be configured to deliver a medical device to the site.

In some over-the-wire procedures, an elongate tapered dilator/introducer system may be used to initiate vascular access and navigate patient vasculature. Using such a system, a guidewire is inserted in the vessels of the patient and guided to the right atrium of the heart. A tapered dilator is inserted into an elongate tubular introducer, with the tapered tip of the dilator extending beyond the tip of the introducer. The guidewire, which is already in the body of the patient, is inserted through the dilator, and the dilator/introducer are navigated over the guidewire into the body. Once the tip of the introducer is positioned in the heart, the guidewire and the dilator are removed, leaving the tubular introducer in place. A deployment catheter including a distal delivery cup housing the leadless pacemaker is then moved through the introducer into the heart, and the leadless pacemaker is anchored at a target implantation site.

In some patients, vascular access can present a clinical challenge in the implantation of a medical device. In some cases, the outer diameter of the dilator/introducer system used to implant a medical device such as a leadless pacemaker can be up to about 32 French (Fr) (10.7 mm). If a patent has distorted or tortuous vessels, or even smaller vessels, guiding the dilator/introducer system to an implantation site to deploy the medical device can be difficult, even with the assistance of a guidewire. The large outside diameter of the dilator/introducer system may increase the difficulty of navigating the system through the vessels of a patient and may increase the possibility of vascular damage. For at least these reasons, practitioners have not often used over-the-wire guidance to deploy larger medical devices such as leadless pacemakers.

In general, the present disclosure is directed to a shuttle apparatus that replaces, and eliminates the need for, the dilator/introducer system that practitioners currently rely on to navigate through patient vasculature and into the heart for implantation of a medical device. The shuttle apparatus of the present disclosure releasably engages a container on a delivery catheter configured to deploy a medical device such as, for example, a leadless pacemaker. The shuttle apparatus includes a distal end including a tapered semiconical introducer member that may be easily maneuvered through the vessels of a patient during an implantation procedure. The shuttle apparatus further includes a proximal end with a hollow frustoconical plug member shaped to fit into a bore in the container, and this plug member is also shaped such that the shuttle apparatus can be easily retracted from the vessels of the patient following implantation of the medical device. The shuttle apparatus further includes a collar member with a distal portion on the introducer member and a proximal portion on the plug member. The collar member engages an elongate tubular guidewire conduit so that a practitioner can utilize a system including the shuttle apparatus and medical device delivery catheter to implant the medical device using an over-the-wire implantation procedure.

Since the shuttle apparatus eliminates the need for the dilator/introducer, and fits within the bore in the container on the delivery catheter, the diameter of a system including the shuttle apparatus and the medical device delivery catheter has a reduced outside diameter. For example, in some implantation systems configured to deploy a medical device such as a leadless pacemaker, the overall outside diameter of a system including the shuttle apparatus and a delivery cup housing the leadless pacemaker is no more than about 30 Fr (10 mm), a reduction of about 6% compared to a conventional dilator/introducer system. In addition, since the dilator/introducer is not needed, the French size of the outside diameter of the system proximal the delivery cup is even smaller, which can ease navigation of the system through the vasculature of the patient. For example, in many cases the outside diameter of the system including shuttle apparatus and delivery catheter does not exceed the outside diameter of the delivery cup or the delivery catheter themselves, which can be as small as 18 Fr (6 mm). In addition, the shuttle apparatus is more flexible than the tubular introducer in a region distal the delivery cup, which can further simplify navigation and placement of the delivery cup.

The semiconical introducer member includes a tapered distal tip so that the shuttle apparatus can be navigated through patient vasculature to a preferred implant site for the medical device. Once the container or delivery cup for the medical device has reached the preferred implant site, the shuttle apparatus may be ejected from the delivery cup, and in some examples can provide a radiopaque marker to assist a practitioner in finding a preferred implant site in the heart. Following implantation of the medical device, the frustoconical plug member includes a tapered surface so that the shuttle apparatus may be quickly and easily extracted from patient vasculature. The collar member on the shuttle apparatus provides secure engagement with a guidewire for both guidance to the implant site and removal following implant, which makes the shuttle apparatus of the present disclosure highly useful for over-the-wire implantation procedures.

In addition, in some examples the shuttle apparatus may be produced by a process such as, for example, injection molding, using readily available and inexpensive polymeric materials.

In some examples, the implantation system of the present disclosure further includes an optional introducer sleeve that can be slidably moved over an external surface of the delivery catheter including the distal container or delivery cup. The introducer sleeve can increase the column strength of the catheter as the implantation system is navigated through patient vasculature, and can be moved along the catheter to a desired location to change a radius of curvature of the delivery catheter and improve the positioning of the container or delivery cup.

In one aspect, the present disclosure is directed to a shuttle apparatus configured to detachably engage a delivery system for an implantable medical device. The shuttle apparatus includes a distal portion having a generally semiconical introducer member with a proximal base and a distal apex; a proximal portion including a hollow, generally frustoconical plug member with a base adjacent to the base of the introducer member; and a collar member with a distal end on the introducer member and a proximal end on the plug member, wherein the proximal end of the collar member includes a cantilevered arm.

In another aspect, the present disclosure is directed to a system for delivery of a leadless pacemaker. The system includes a catheter having an elongate flexible tubular body with a proximal end and a distal end, wherein the distal end of the tubular body includes a container configured to releasably retain therein the leadless pacemaker, and wherein the container has a longitudinal bore extending from a proximal end to a distal end thereof; a shuttle apparatus configured for releasable insertion into the container of the catheter, wherein the shuttle apparatus includes a distal end with a tapered introducer member, a proximal end with a plug member adjacent to the introducer member and an external surface configured to fit within the bore in the container; and a collar member with a cylindrical bore configured to engage a guidewire or guidewire conduit, the collar member having a distal end that extends along an altitude of the introducer member, and a proximal end that extends over the plug member, wherein the proximal end of the collar member includes a cantilevered arm deflectably moveable into and out of engagement with the container.

In another aspect, the present disclosure is directed to a method for implanting a leadless pacemaker. The method includes inserting a distal end of a guidewire into vasculature of a patient; inserting a proximal end of the guidewire into a collar member on a shuttle apparatus and into a guidewire conduit attached to the collar member, wherein the collar member has a cantilevered arm clampable against an external surface of a container housing the leadless pacemaker, the shuttle apparatus further including: a distal end with a generally semiconical introducer member, and a proximal end with a generally frustoconical plug member, wherein the plug member has an external surface configured to fit in a bore of the container; translating the container over the guide wire and through the vasculature of the patient to an implant site; ejecting the shuttle assembly from the container; deploying the leadless pacemaker from the container; implanting the leadless pacemaker at the implant site; removing the catheter from the vasculature of the patient; and withdrawing the guidewire conduit and the shuttle apparatus attached thereto from the vasculature of the patient.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

Like symbols in the drawings indicate like elements.

is a schematic illustration (which is not to scale) of a conventional systemfor guiding a medical device through vasculature of a patient to a target tissue location for implantation. While the present disclosure exemplifies systems and methods for implantation of leadless pacemakers, it should be understood that the systems of the present disclosure can be utilized to implant any type of medical device such as, for example, temporary or permanent pacemakers with leads, cardiac monitors, pressure sensors, cardiac defibrillators, stents including coronary stents, joint implants, interocular lenses, neurostimulators, pumps, and the like.

In the example of, the systemis configured to deliver a leadless pacemaker to a desired implant location so that the leadless pacemaker may be implanted into a target cardiac tissue. The systemincludes an elongate tubular catheterhaving a bodywith a borethat extends from a proximal endto a distal endthereof. In some examples, which are not intended to be limiting, the catheter bodyhas a length of about 75 centimeters (cm) to about 150 cm.

The proximal endof the catheter bodyis connected to a control handlethat can be used to deflect the catheter bodyand deploy a pacing capsule. The pacing capsuleis releasably retained at the distal endof the catheter bodyin a delivery cup or container. Suitable leadless pacemaker pacing capsulesinclude, but are not limited to, those available from Medtronic, Inc., Minneapolis, MN, under the trade designation MICRA. The pacing capsuleincludes a self-contained pulse generator, electronics for control of the pacemaker and electrode system that is implantable into cardiac tissue, and do not require leads or a subcutaneous pacemaker pocket like a transvenous pacemaker system.

The catheter bodymay be placed in a suitable vein of a patient such as, for example, the femoral vein, and moved through the venous system to place a distal endof the delivery cupat a predetermined location in the heart. In some examples, the catheter bodymay be deflected using an optional curve deflection controlon the handle. In some examples, the location of the catheter bodyand a distal regionof the delivery cupis monitored with a fluoroscopic and/or ultrasonic imaging system, and an X-ray or sonogram image of the catheter bodyand the delivery cupis used to precisely position the delivery cupin the heart. In some embodiments, during placement procedures a proximal portion of the pacing capsulecan optionally be tethered via a mechanical tether (not shown in) such as, for example, a tether pin.

Once the delivery cupis positioned at within a selected region of the heart such as, for example, the Triangle of Koch (TOK) region or the coronary sinus, the pacing capsuleis deployed from the delivery cupvia manipulation of the pacing capsuleor engagement of an optional deployment controlon the handle. The pacing capsulecan be implanted into the cardiac tissue using, for example, an arrangement of spring-loaded or self-expanding metal tines, a screw-in metal helix, and combinations thereof. After the pacing capsuleis implanted in the target tissue of the heart, a tether lockon the handleis released, and the catheter bodyis withdrawn from the vascular system of the patient. The pacing capsule remains in position within the heart to provide suitable pacing therapy for the patient.

In some examples, the handlemay optionally include a fluid port, which can provide a fluid flush through the boreof the catheter bodyusing a fluid such as, for example, water, saline, and the like.

show a shuttle apparatusthat includes a distal portionand a proximal portion. The distal portionincludes a generally semiconical introducer member, and the proximal portionincludes a generally frustoconical plug member. A collar memberincludes a distal portionattached to the introducer member, and a proximal portionattached to the plug member.

The semiconical introducer member, which has the shape of a portion of a cone, has a diameter that tapers from a maximum at a proximal semi-circular baseto a minimum at a distal tip. The introducer memberincludes a curved external surface, and a wallof the introducer member has a non-linear arcuate shape. The narrow diameter of the distal tipand the shape of the arcuate wallmake the introducer memberatraumatic to patient vasculature as the shuttle apparatusis pushed along a distal direction (arrow A in) in an implantation procedure. The introducer memberfurther includes an annular shelf portionthat extends in a direction normal to a longitudinal axis of the shuttle apparatus.

In some examples, the arcuate wallcan include an optional port. In some examples, the port, which extends along a direction normal to the longitudinal axisof the shuttle apparatus, may be filled with a radiopaque material such as a metal or metal alloy, to provide fluoroscopic location information about the position of the shuttle apparatuswithin the vessels or heart of the patient.

The frustoconical plug memberhas a diameter that tapers from a maximum at a baseto a minimum at an annular apex portion. The annular apex portionis oriented at an acute angle with respect to a baseof the plug member, and at an obtuse angle with respect to the longitudinal axisof the shuttle apparatus.

The annular apex portionbounds a bore, which extends through the plug memberand the introducer member. In some examples, the boremay be used to flush the shuttle apparatusduring an implantation procedure with a fluid such as water, saline, and the like.

The plug memberfurther includes a wallextending from the baseto the annular apex portion. The wallis sized and configured to fit within an internal surface of a bore of a delivery container or cup on a delivery catheter for implantation of a medical device (shown in more detail below). The wallhas a smooth, rounded shape such that the shuttle devicemay be pulled in a proximal direction (arrow B in) without causing undue trauma to the vasculature of a patient. In some examples, the wallmay optionally have a shape, be made of selected materials, or have a surface texture, selected to provide a friction fit with the internal bore of the delivery cup for the medical device.

The wallof the plug portionfurther includes an arcuate rampthat extends away from the annular apex portionand extends to a shoulder. The shoulder, which is shown in more detail below, extends in a direction generally normal to the longitudinal directionof the shuttle apparatus.

The collar memberof the shuttle apparatuscontacts and extends over both the introducer memberand the plug member, and includes a generally tubular boretraversing the full length of the collar member. The tubular boreis configured to retain an elongate tubular conduit that retains a guidewire (not shown in, shown in more detail below). The guidewire is confined within the tubular conduit, and moves slidably therewithin during implantation procedures such that the shuttle apparatuscan move freely along the length of the guidewire. The distal portionof the collar memberextends generally along a height or altitude of the semiconical introducer portion, and terminates at the distal tipof the introducer member. The proximal portionof the collar memberextends beyond the wallof the plug memberand forms a cantilevered arm.

As explained in more detail below, the cantilevered armis formed of a material that may be displaced up and down along a direction generally normal to the longitudinal axisof the shuttle apparatusto apply or release a retaining force on a delivery cup retaining an implantable medical device. In the embodiment of, as discussed in more detail below, the cantilevered arm includes a tabthat extends along a direction generally normal to the longitudinal axisof the shuttle apparatus, and forms a component of a snap-fit connector with a corresponding receptacle in a wall of a delivery cup retaining an implantable medical device. In some examples, the tabincludes an angled engagement surfaceto facilitate engagement and disengagement from the corresponding receptacle in the delivery cup.

The introducer member, the plug member, and the collar memberof the shuttle apparatusmay be made from a wide variety of materials such as, for example, polymers, or metals such a stainless steel, titanium, or mixtures and alloys thereof. In some examples, the introducer member, the plug memberand the collar membermay each be formed from a relatively hard medical grade plastic, such as 72D PEBAX, Delrin or Nylon, for example, by injection molding. The material may include radiopaque additives and/or echogenic additives to allow the shuttle apparatus to be more visible under fluoroscopy and/or ultrasound.

In some examples, each member of the shuttle apparatus may be formed from the same or different materials. For example, the size, thickness, shape, and material composition of the cantilevered armmay be selected to provide a predetermined amount of engagement force on a delivery cup, while the composition of the wallof the introducer portionmay be formed from a softer material than the material selected to make the cantilevered arm. In another example, the wallof the plug portionmay be formed of a material selected to provide a frictional fit of the plug portionand a delivery cup or container into which the plug portionis to be inserted.

illustrate a medical device implantation systemincluding the shuttle apparatusofdiscussed above. Referring now to the exploded view in, the systemincludes the shuttle apparatus, which is configured to releasably engage a delivery cup or containeron a distal end of a delivery catheter. The delivery cuphouses an implantable medical device such as, for example, a leadless pacemaker. A distal endof the leadless pacemakerincludes a helically arranged tineshaped to anchor the pacemakerat a target implantation site in the heart of a patient such as, for example, in a coronary sinus region, a triangle of Koch (TOK) region, and the like. A proximal endof the pacemakeris configured for releasable attachment to a tether. A guidewire conduitis retained in the tubular channelof the collar memberof the shuttle apparatus. A guidewiremoves slidably within the conduitsuch that the shuttle apparatusis retained thereon, but can be moved freely along the length of the guidewire.

The delivery cupincludes a bodywith a proximal endconnected to the delivery catheter, a distal end, and a longitudinal boreextending therethrough. The boreincludes an internal wall.

The distal endof the bodyincludes a linear notchextending generally along a longitudinal axisof the system. The notchextends from a distal edgeof the delivery cup body, and terminates in a U-shaped shaped stop. The bodyof the delivery cupfurther includes a receptacle, which is proximal of the notchand aligned therewith. The receptacle, which is shaped to engage with the tabon the cantilevered armof the shuttle apparatus, extends through the bodyof the delivery cup, and forms a component of a snap fit connector with the tab.

illustrate the systemwith the leadless pacemakerand the plug memberof shuttle apparatusfully inserted into the borein the delivery cup. As shown in, when the shuttle apparatusis inserted in the bore, the distal edgeof the bodyof the delivery cupabuts the annular ledge portionin the wallof the plug member. Helical tineon the leadless pacemakerextends into the borein the plug member.

As the shuttle apparatusis inserted into the borein the delivery cup, the tabis guided along and retained within the linear notch. When the tabencounters the U-shaped stop, the angular engagement surfaceon the tabis urged upward, which in turn urges the cantilevered armin a direction along arrow C normal to the longitudinal axisof the system. When the tablies over the receptaclein the delivery cup, the taband the cantilevered armmove along the direction D, and the tabsnaps into engagement and is retained in the receptacle. The tabon the cantilevered armand the receptaclethus form a snap-fit connector that retains the plug memberof the shuttle apparatuswithin the boreof the delivery cup. When the tabsnaps into place in the receptacle, the distal edgeof the delivery cupabuts the annular shelf portionon the plug member, and the wallof the plug memberfully fits within the interior wallof the delivery cup.

As shown in detail in, when the tabis engaged in the receptacle, a distal shoulderof the leadless pacemakeris positioned adjacent to the shoulderon the wallof the plug member. As discussed in more detail below, when the leadless pacemakeris advanced distally and moved out of the delivery cup, the distal shoulderengages the shoulderon the plug member, which has the effect of urging the cantilevered armaway from the delivery cup. As the leadless pacemakeris moved in a more distal direction and pushes up the shoulder, the shoulderfurther engages the arcuate ramp, which in the example ofincludes a linear portiongenerally parallel to the longitudinal axis, and an arcuate sectionconnected to the linear portion.

Referring now to, as the leadless pacemakeris pushed along a distal direction A, the leadless pacemakeremerges from the distal endof the delivery cup. The distal shoulderof the pacemakeris urged against the shoulderon the wallof the plug member, which deflects the cantilevered armupward along the direction of arrow C. As the cantilevered arm is deflected upward, the tabthereon also moves upward and begins to disengage from the receptaclein the wallof the delivery cup. As the leadless pacemakeris pushed further in the distal direction A, the distal shoulderthereof engages the arcuate rampon the wallof the plug member, which causes the shuttle apparatusto tilt upward along the direction C and urges the distal edgeof the delivery cupagainst the annular ledge portionon the plug member, while further lifting the cantilevered armand fully disengaging the tabfrom the receptaclein the delivery cup. Further distal movement along the direction of the arrow A of the leadless pacemakerurges the plug memberout of the borein the delivery cupand fully disengages the shuttle apparatusfrom the delivery cup. The disengaged shuttle apparatus, which is attached to and suspended on the guidewire conduit(), falls away from the borein the delivery cupand exposes tineon the leadless pacemaker. Tinemay then be employed to implant the leadless pacemakerinto a target tissue in the heart, e.g. via further operation of the medical device implantation system.

Referring now to, in another example a systemincludes a shuttle apparatuswith an introducer member, a plug member, and a collar member. The collar memberincludes a tubular channelconfigured to retain a guidewire conduit. The shuttle apparatusis configured such that the plug memberon the shuttle apparatusis releasably retained in a borein a delivery cupretaining a leadless pacemaker with tissue-piercing tines.

In the embodiment of, the collar memberincludes a cantilevered armformed from a resilient material. Unlike the cantilevered armdescribed inabove, the cantilevered armin the systemis free of snap-fit connector features configured to releasably engage the delivery cup.

As shown in, prior to insertion of the plug memberinto the delivery cup or container, the resilient cantilevered armis in a relaxed state and deflected downward in a direction along arrow D normal to a longitudinal axisof the system.

Referring now to, as the shuttle apparatusis moved proximally in a direction along arrow B, the resilient cantilevered armengages with an exterior surfaceof the delivery cup. The exterior surfaceurges the cantilevered armupward along the direction of arrow C normal to the longitudinal axisof the system. The upward movement takes the cantilevered armout of its original relaxed state, and the deflected armapplies a downward clamping force along the direction of the arrow D against the exterior surfaceof the delivery cup.

As shown in, as the shuttle apparatusis moved further in a proximal direction (arrow B), the resilient cantilevered armextends along the exterior surfaceof the delivery cup, and exerts an increasing clamping force on the surfacealong a direction of the arrow D. The clamping force between the resilient cantilevered armand the exterior surfaceof the delivery cupretains the plug memberin the boreof the delivery cup, and maintains the position of the shuttle apparatusin the delivery cup. The distal edgeof the delivery cupabuts the annular ledge portionon the plug portion, and the helical fixation tineis housed in the borein the plug portion.

When the leadless pacemaker is pushed distally along the direction of arrow A and is deployed from the delivery cup, the clamping force between the resilient cantilevered armand the surfaceof the delivery cupis overcome, and the shuttle apparatusis pushed distally along the direction of arrow A and is expelled from the boreof the delivery cup, exposing the fixation tine. The leadless pacemaker may then be implanted in a target tissue using the exposed fixation tine.

After deployment of the leadless pacemaker, shuttle apparatusmay be removed from the body. In some examples, shuttle apparatusmay include a feature configured to surround the proximal end of the shuttle to allow it to be withdrawn from the vessel without an edge or cavity of shuttle apparatusengaging or snagging any tissue. For example, the feature may include an expandable sleeve that has an inner diameter greater than the outer diameter of the guidewire conduit. This sleeve, which may be formed from a compliant material, may be configured to expand and fold over the proximal end of shuttle apparatuswhen the sleeve is compressed. In this way, the feature may effectively block any edges or cavities of shuttle apparatusfrom engaging tissues when shuttle apparatusis withdrawn from the vessel. In one example, the feature may include a soft mesh that expands on compression. In another example, the feature may define multiple slits that enable the feature to collapse longitudinally but expand radially.

In some examples, the shuttle apparatus of the present disclosure can be used to drive a leadless pacing device (such as, for example, those available from Medtronic, Minneapolis, MN, under the trade designation Micra) delivery system over a guidewire in an over-the-wire implantation procedure. The shuttle apparatus of the present disclosure also eliminates the need to utilize a dilator/introducer, which increase the outside diameter of the delivery system for the implantable medical device. The larger diameter delivery system makes navigation of the delivery cup through patient vasculature more difficult, and can increase the likelihood of vascular injury during implantation procedures, while enabling the procedure to be performed with a smaller, faster-healing vascular access opening.

The shuttle apparatus of the present disclosure can also optionally be configured to provide fluoroscopic and/or sonographic location information about the location of the delivery capsule, and even after the shuttle apparatus is ejected from the delivery capsule, the shuttle apparatus remains in the heart to provide location information useful in identifying a preferred implantation site. The attached guidewire also makes the shuttle apparatus easily removable from the vasculature of the patient following implantation of the leadless pacemaker.